Postpartum hypoglycemia is a frequent complication in pregnancy complicated by Type I diabetes. Although the antepartum increase in insulin resistance is well-documented, little is known about insulin sensitivity in the postpartum period. Placental GH shares many of the biologic properties of pituitary GH, and is secreted in increasing amounts during pregnancy. Its disappearance from the circulation coincides with the time period of frequent hypoglycemia. We plan to measure insulin sensitivity in women with and without Type I diabetes mellitus.